Device and method for controlling a two cylinder thick matter pump
AssigneePutzmeister Concrete Pumps GmbH
InventorsStefan Hoefling, Wilhelm Hofmann, Wolf-Michael Petzold
Life of this patent
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Abstract
A device and a method for controlling a two-cylinder thick matter pump comprising pistons that are actuated in a push-pull manner by means of a hydraulic reversible pump (6) and hydraulic drive cylinders controlled by said pump. To ensure a reliable operation of the pump the expected length of the stroke of the pistons (8, 8′) in the drive cylinders (5, 5′) is measured and recorded, the stroke time of each conveyance stroke is monitored and compared with the expected stroke duration, and the reversible pump (6) is respectively pivoted, reversing the flow, and/or the pipe switch (56) is reversed when the stroke time exceeds the expected stroke duration by a pre-determined value.
Claims19
A thick matter pump with two conveyor cylinders (50, 50′) communicating via two end openings (52) in a material supply container (54), the two conveyor cylinders (50, 50′) operated in counter stroke by a hydraulic reversible pump (6) via hydraulic drive cylinders (5, 5′) driven by said pump, with a hydraulically actuated pipe switch (56) provided within the material supply container (54), the pipe switch having an inlet and an outlet, the pipe switch inlet being alternatingly connectable to one of the openings (52) of the conveyor cylinders (50, 50′), freeing the respective other opening of the conveyor cylinders (50, 50′), and the pipe switch outlet being connected with a conveyor conduit (58), wherein the drive cylinders (5, 5′) are each hydraulically connected at one end with an opening of the reversible pump (6) via respectively one hydraulic line (11, 11′), and wherein the drive cylinders (5, 5′) on their other end are connected to each other via an oscillating oil line (12),
- and further comprising a reversing device (18) for reversing the reversible pump (6) after the conclusion of each piston stroke,
- wherein the reversing device includes a computer assisted routine (84, 82) for determining an expected stroke duration and for the recording thereof in a data storage as well as for monitoring the time during each piston stroke, and initiating a reversal of at least one of (a) the pipe switch (56) and (b) the flow through reversal of the reversible pump (6) based on a comparison of the value of an elapsed stroke time with the expected stroke duration.
A device for controlling a thick matter pump with two conveyor cylinders (50, 50′) communicating with two end openings (52) in a material supply container (54), operated in counter stroke via a hydraulic reversible pump (6) and via hydraulic drive cylinders (5, 5′) having pump ends and rod ends and driven by the hydraulic reversible pump (6), with a hydraulically operated pipe switch (56) provided within the material supply container (54), the pipe switch having an inlet and an outlet, the pipe switch inlet being alternatingly connectable to one of the openings (52) of the conveyor cylinders (50, 50′), freeing the respective other opening of the conveyor cylinders (50′, 50), and the pipe switch outlet being connected with a conveyor conduit (58), wherein the drive cylinders (5, 5′) are each hydraulically connected at their pump end with an opening of the reversible pump (6) via respectively one hydraulic line (11, 11′), and the drive cylinders (5, 5′) are hydraulically connected to each other at their rod ends via an oscillating oil line (12), with at least two cylinder switch sensors (20, 20′;
- 22, 22′) in predetermined separation from each other and from the rod and/or pump ends of the drive cylinder (5, 5′) responding to the passing by of a piston (8, 8′) of the drive cylinder, and with a computer assisted reversal device (18) responsive to the output signal of selected cylinder switch sensors for switching or reversing the reversible pump and the pipe switch (56) after completion of a piston stroke, characterized by at least one sensor for monitoring the hydraulic pressure on the high pressure side (70) of the reversible pump (6) of which the output signal can be evaluated with a pressure monitoring routine (80) of the computer assisted reversal device (18) for initiating at least one of (a) a reversal of the pipe switch (76) and (b) a flow-through reversal of the reversible pump (6).
A process for controlling a thick matter pump with two conveyor cylinders (50, 50′) of which two end openings (52) are in communication in a material supply container (54), operated in counter stroke via a hydraulic reversible pump (6) and via hydraulic drive cylinders (5, 5′) driven by the hydraulic reversible pump (6), with a pipe switch (56) provided within the material supply container (54), the pipe switch having an inlet and an outlet, the pipe switch inlet being alternatingly connectable to one of the openings (52) of the conveyor cylinders (50, 50′), freeing the respective other opening of the convey or cylinders (50, 50′), wherein respectively upon ending of a conveyance stroke in the conveyor cylinders (50, 50′) a reversal process of the pipe switch (56) and/or the reversible pump (6) is initiated, said process comprising:
- measuring and recording, during calibration of the concrete pump and/or during the pump operation, the stroke duration of the piston (8, 8′) in the drive cylinders (5, 5′) and recording this in memory as the expected stroke duration,
- monitoring during each conveyance stroke the stroke time and comparing monitored stroke time with the expected stroke duration, and
- reversing the reversible pump (6) with reversal of the flow-through and/or pivoting the pipe switch (56) to the alternate opening when the stroke time exceeds the expected stroke duration by a predetermined value.
A process for controlling a thick matter pump with conveyor cylinders (50, 50′) of which two end openings (52) are in communication in a material supply container (54), operated in counter stroke via a hydraulic reversible pump (6) and via hydraulic drive cylinders (5, 5′) driven by the hydraulic reversible pump (6), with a hydraulically operated pipe switch (56) provided within the material supply container (54), the pipe switch having an inlet and an outlet, the pipe switch inlet being alternatingly connectable to one of the openings (52) of the conveyor cylinders (50, 50′), freeing the respective other opening of the conveyor cylinders (50′, 50), and the pipe switch outlet being connected with a conveyor conduit (58), the process comprising:
- initiating, respectively upon ending of a conveyance stroke in the conveyor cylinders, a reversal process of the pipe switch (56) and/or the reversible pump (6),
- monitoring during the pump process the hydraulic pressure of the reversible pump (6), and
- evaluating a pressure increase measured at the end of each piston stroke and converting the pressure increase into a reverse signal (76) for the reversible pump (6) and/or the pipe switch (56).
Dependencies are inferred from the claim text.